Summary of the meeting of the VDT Regional Association Berlin at the TU Berlin

Topic: New research on the acoustics of musical instruments - sound power, directivity, near field

Text: Theo Schulte, Peter Weinsheimer; Photos: Georg Fett, Theo Schulte, Peter Weinsheimer

On February 19, 2025, around 30 interested people gathered at the TU Berlin for an event organized by the VDT Berlin. The hosts were Prof. Stefan Weinzierl and David Ackermann from the Department of Audio Communication, who presented the latest research findings on the sound power and directional characteristics of musical instruments.

The tour began in the acoustic test hall of the TU; in the reverberation room and in the large anechoic chamber. Despite the background noise from those present in the latter, which meant that the charm of the anechoic environment did not quite materialize, the view was impressive, almost floating in the middle of the large pyramid-shaped absorbers.

In the subsequent lecture, the dynamic ranges of historical and modern instruments were compared in order to investigate changes in the orchestral balance. While clarinets, for example, still have the largest dynamic range, the ratio between strings and woodwinds has remained surprisingly constant over the centuries. However, today's performance practice - with larger string sections and more assertive brass - may have placed greater tonal demands on the woodwinds.

Another topic was the directional characteristics of instruments, which - unlike loudspeakers - change dynamically due to pitch, texture, such as flaps or holes, and movement. These aspects are essential for virtual acoustics and realistic simulations. Near-field effects, which differ from the typical far-field properties, are just as relevant. The Rayleigh integral can be used to show that sound radiation does not follow the classic 1/R law: Spectral distortions occur in the near field, which are influenced by frequency, source size and distance. If the wavelengths are in the range of twice the distance difference between two points on the surface of a sound source, cancellations occur. In the case of the double bass, this can lead to unexpected changes in sound at high frequencies - an important aspect for miking and sound design.

An in-depth article on these research findings is in preparation and will be published in the upcoming VDT magazine.

After this informative excursion, this and other topics were discussed further in a Greek restaurant.

Event in German language.

Original-Einladung: Führung und Fachvortrag an der TU Berlin

Thema: Reflexionsarmer Raum & Akustische Forschung

Unser heutiger Gastgeber, Stefan Weinzierl (Leiter des Fachgebiets Audiokommunikation an der TU Berlin) lädt uns zu einem Nachmittag rund um die Akustik von Musikinstrumenten ein. Er beginnt mit einer Führung durch die Akustik-Prüfhalle einschließlich des großen reflexionsarmen Raums.

Im Anschluss gibt uns Stefan Weinzierl mit seinem Vortrag zum Thema „Reflexionsarmer Raum und akustische Forschung“ Einblicke in die aktuellen Forschungen der TU zur Akustik von Musikinstrumenten und Konsequenzen für die Aufnahmepraxis. Dabei geht es einerseits um die Schallleistung und die Richtcharakteristik von modernen und historischen Musikinstrumenten und deren Darstellung in akustischen Simulations- und Auralisationswerkzeugen, andererseits um das unterschiedliche Verhalten von Musikinstrumenten im Nahfeld und im Fernfeld sowie deren Auswirkungen auf Mikrofonierung und Klangbild. An den Vortrag schließt sich wie immer eine Diskussionsrunde an.

Die vorgestellten Erkenntnisse liefern Anregungen und Denkanstöße, die sich sicherlich auf unsere berufliche Praxis übertragen lassen. Es erwartet uns ein spannender Abend mit fachlichen Erkenntnissen und kollegialem Austausch.

Treffpunkt ist der Parkplatz vor der Akustik-Prüfhalle, über die Einfahrt Einsteinufer 31.

Bittemeldet euch vorab hier an:

Wir freuen uns auf eure Teilnahme!

Peter Weinsheimer und Roman Rehausen
Regionalleitung Berlin